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transcranial ultrasound

Daniel Silva de Azevedo, Angela Salomao Macedo Salinet, Marcelo de Lima Oliveira, Manoel Jacobsen Teixeira, Edson Bor-Seng-Shu, Ricardo de Carvalho Nogueira
Cerebral microcirculation is gradually compromised during sepsis, with significant reductions in the function of capillaries and blood perfusion in small vessels. Transcranial Doppler ultrasound (TCD) has been used to assess cerebral circulation in a typical clinical setting. This study was to systematically review TCD studies, assess their methodological quality, and identify trends that can be associated with the temporal evolution of sepsis and its clinical outcome. A meta-analysis of systematic reviews was conducted according to the PRISMA statement...
October 18, 2016: Journal of Clinical Monitoring and Computing
Rachel Wong, Rhenan Nealon, Daniel Raederstorff, Peter Howe
OBJECTIVE: Having shown that resveratrol consumption can improve flow mediated dilation of the brachial artery, we tested its effects on CVR to hypercapnia in adults with T2DM, a risk population for cerebrovascular disease and cognitive impairments. DESIGN AND METHOD: In a double-blind crossover trial, 34 adults with T2DM consumed 0, 75, 150 and 300 mg of synthetic trans-resveratrol (one dose per week in random order). Before and 1-2 hr after dosing, transcranial Doppler ultrasound was used to assess CVR to a hypercapnic stimulus (breathing Carbogen gas for 3 min) in the middle (MCA) and posterior (PCA) cerebral arteries...
September 2016: Journal of Hypertension
Georgios Tsivgoulis, Andrei V Alexandrov
PURPOSE OF REVIEW: Low cost, avoidance of irradiation, and high temporal resolution are inherent advantages of ultrasound imaging that translate into multiple clinical uses in many domains of neurology. This article presents clinical uses of ultrasound examination in cerebrovascular, neurodegenerative, and peripheral nervous system diseases. RECENT FINDINGS: Modern treatment and prevention of ischemic stroke rely on prompt diagnosis. Ultrasonography has found a place as a noninvasive screening test and bedside technique that provides estimates of the degree of stenosis as well as hemodynamic and structural information about intracranial and extracranial vessels in real time...
October 2016: Continuum: Lifelong Learning in Neurology
Nathan McDannold, Margaret Livingstone, Can Barış Top, Jonathan Sutton, Nick Todd, Natalia Vykhodtseva
This study investigated thermal ablation and skull-induced heating with a 230 kHz transcranial MRI-guided focused ultrasound (TcMRgFUS) system in nonhuman primates. We evaluated real-time acoustic feedback and aimed to understand whether cavitation contributed to the heating and the lesion formation. In four macaques, we sonicated thalamic targets at acoustic powers of 34-560 W (896-7590 J). Tissue effects evaluated with MRI and histology were compared to MRI-based temperature and thermal dose measurements, acoustic emissions recorded during the experiments, and acoustic and thermal simulations...
October 14, 2016: Physics in Medicine and Biology
Elisabeth B Marsh, Wendy C Ziai, Rafael H Llinas
INTRODUCTION: Reversible cerebral vasoconstriction syndrome (RCVS) typically affects young patients and left untreated can result in hemorrhage or ischemic stroke. Though the disorder has been well characterized in the literature, the most appropriate way to diagnose, treat, and evaluate therapeutic response remains unclear. In previous studies, transcranial Doppler ultrasound (TCD) has shown elevated velocities indicative of vasospasm. This imaging modality is noninvasive and inexpensive; an attractive option for diagnosis and therapeutic monitoring if it is sensitive enough to detect changes in the acute setting given that RCVS often affects the distal vessels early in the course of disease...
May 2016: Case Reports in Neurology
Michael Marx, Pejman Ghanouni, Kim Butts Pauly
PURPOSE: MR thermometry is critical for safe and effective transcranial focused ultrasound. The current single-slice MR thermometry sequence cannot achieve all desired treatment monitoring requirements. We propose an approach in which the imaging requirements of different aspects of treatment monitoring are met by optimizing multiple sequences. METHODS: Imaging requirements were determined for three stages of MR-guided focused ultrasound brain treatment: 1) focal spot localization, 2) focal spot monitoring, and 3) background monitoring...
October 4, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Elena Cela, Ana G Vélez, Alejandra Aguado, Gabriela Medín, José M Bellón, Cristina Beléndez
BACKGROUND AND OBJECTIVE: Sickle cell anaemia causes progressive organ damage. The objective is to describe school performance of patients with sickle cell anaemia and their clinical parameters and quality of life that may have an influence. The hypothesis is that if school alterations occur without other objective data, additional factors must be present besides the disease itself. PATIENTS AND METHODS: Transversal study performed in November 2015 considering analytical variables, complications and neuroradiological images of children with sickle cell anaemia, and family survey on school performance and quality of life...
September 29, 2016: Medicina Clínica
P E Frid, S J Schreiber, O Pade, F Doepp, J Valdueza
PURPOSE: To differentiate PCA segments and cortical branches by means of transcranial color-coded duplex sonography (TCCD) and to measure flow parameters at rest and during visual stimulation. MATERIALS AND METHODS: 60 healthy subjects with a good acoustic temporal bone window were examined. The main stem of the PCA (P1, P2 and P3) and 4 main cortical branches - the anterior temporal artery (ATA), the occipital temporal artery (OTA), the parietooccipital artery (POA) and the calcarine artery (CA) - were assessed using an axial transtemporal approach...
November 2015: Ultrasound Int Open
Wonhye Lee, Hyun-Chul Kim, Yujin Jung, Yong An Chung, In-Uk Song, Jong-Hwan Lee, Seung-Schik Yoo
Transcranial focused ultrasound (FUS) is making progress as a new non-invasive mode of regional brain stimulation. Current evidence of FUS-mediated neurostimulation for humans has been limited to the observation of subjective sensory manifestations and electrophysiological responses, thus warranting the identification of stimulated brain regions. Here, we report FUS sonication of the primary visual cortex (V1) in humans, resulting in elicited activation not only from the sonicated brain area, but also from the network of regions involved in visual and higher-order cognitive processes (as revealed by simultaneous acquisition of blood-oxygenation-level-dependent functional magnetic resonance imaging)...
2016: Scientific Reports
Rachel Wong, Rhenan Nealon, Daniel Raederstorff, Peter Howe
OBJECTIVE: Having shown that resveratrol consumption can improve flow mediated dilation of the brachial artery, we tested its effects on CVR to hypercapnia in adults with T2DM, a risk population for cerebrovascular disease and cognitive impairments. DESIGN AND METHOD: In a double-blind crossover trial, 34 adults with T2DM consumed 0, 75, 150 and 300 mg of synthetic trans-resveratrol (one dose per week in random order). Before and 1-2 hr after dosing, transcranial Doppler ultrasound was used to assess CVR to a hypercapnic stimulus (breathing Carbogen gas for 3 min) in the middle (MCA) and posterior (PCA) cerebral arteries...
September 2016: Journal of Hypertension
P Puz, A Lasek-Bal, P Radecka
BACKGROUND: Transcranial sonography may be applied to assess the basal ganglia nuclei and brain atrophy by the measurement of the width of the third ventricle. The aim of this study was to assess usefulness of transcranial sonography (TCS) in patients with multiple sclerosis (MS) by examining the echogenicity of subcortical structures and the width of the third ventricle. METHOD: Transcranial sonography evaluation of substantia nigra, brain stem raphe nuclei, diameter of the third ventricle, width of the anterior horn of the lateral ventricle, thalamus, lenticular nucleus, and head of the caudate nucleus in 41 patients with relapsing-remitting MS (RRMS), 23 with secondary progressive MS (SPMS), and 20 healthy controls was compared...
September 18, 2016: Acta Neurologica Scandinavica
David Montero, Sven Rauber
BACKGROUND: It remains unknown whether brain perfusion is preserved and mirrored by middle cerebral blood flow velocity (MCA BFV) during prolonged changes in body posture. Herein, we examined the impact of sustained (180 min) 30° head-up (HUT) and head-down (HDT) tilt on brain perfusion, as determined by MCA BFV and blood flow in the extracranial arteries. METHODS: In 10 healthy male subjects, arterial diameters, BFVs, and blood flows were determined in the left internal carotid (ICA) and vertebral (VA) arteries using duplex Doppler ultrasound in supine rest, and 5, 20, 60, 120, and 180 min following 30° HUT and HDT...
August 2016: Aerospace Medicine and Human Performance
Michael M Tymko, Caroline A Rickards, Rachel J Skow, Nathan C Ingram-Cotton, Michael K Howatt, Trevor A Day
Steady-state tilt has no effect on cerebrovascular reactivity to increases in the partial pressure of end-tidal carbon dioxide (PETCO2). However, the anterior and posterior cerebral circulations may respond differently to a variety of stimuli that alter central blood volume, including lower body negative pressure (LBNP). Little is known about the superimposed effects of head-up tilt (HUT; decreased central blood volume and intracranial pressure) and head-down tilt (HDT; increased central blood volume and intracranial pressure), and LBNP on cerebral blood flow (CBF) responses...
September 2016: Physiological Reports
Robert J Adams, Dan T Lackland, Lynette Brown, David Brown, Jenifer Voeks, Heather J Fullerton, Julie Kanter, Janet L Kwiatkowski
In children with Sickle Cell Disease, the combination of risk stratification with Transcranial Doppler Ultrasound (TCD) and selective chronic red cell transfusion (CRCT-the STOP Protocol) is one of the most effective stroke prevention strategies in medicine. How fully it is being implemented is unclear. Nineteen of 26 sites that conducted the two pivotal clinical trials (STOP and STOP II) participated in Post STOP, a comprehensive medical records review assessing protocol implementation in the 10-15 years since the trials ended...
September 13, 2016: American Journal of Hematology
Christina D Bruce, Craig D Steinback, Uday V Chauhan, Jamie R Pfoh, Maria Abrosimova, Emily R Vanden Berg, Rachel J Skow, Margie H Davenport, Trevor A Day
The central respiratory chemoreflex contributes to blood gas homeostasis, particularly in response to accumulation of brainstem CO2 . Cerebrovascular reactivity (CVR) affects chemoreceptor stimulation inversely through CO2 washout from brainstem tissue. Voluntary breath-holding imposes alterations in blood gases, eliciting respiratory chemoreflexes, potentially contributing to breath-hold duration (i.e., break-point). However, the effects of cerebrovascular reactivity on break-point have yet to be determined...
September 12, 2016: Experimental Physiology
Devin S Muntz, David G Bundy, John J Strouse
OBJECTIVES: Transcranial Doppler ultrasound (TCD) effectively identifies children with sickle cell anemia (SCA) who are at increased risk of stroke. We evaluated a low-cost quality improvement (QI) intervention to increase the proportion of children screened by TCD. METHODS: We measured the proportion of children with SCA receiving appropriate TCD screening for increased cerebral blood velocity, a marker of stroke risk, for time periods before (April 1, 2009-July 1, 2010) and after (October 1, 2010-January 1, 2012) the implementation of a QI program...
September 2016: Southern Medical Journal
Przemyslaw Puz, Anetta Lasek-Bal, Tomasz Urbanek, Zofia Kazibutowska
AIM: Carotid artery stenosis can result in the brain tissue injury related to the intracranial aterial flow disturbances as well as microembolic complications. The choice of the proper therapy in patients with carotid artery stenosis, especially asymptomatic, remains still a significant clinical problem. The study aim was an assessment of the cerebral embolism and brain vascular reserve parameters in patients with carotid artery stenosis regarding the occurrence of the clinical symptoms, the degree of stenosis as well as plaque morphology...
2016: Neurologia i Neurochirurgia Polska
Urvi Vyas, Pejman Ghanouni, Casey H Halpern, Jeff Elias, Kim Butts Pauly
PURPOSE: In transcranial magnetic resonance-guided focused ultrasound (tcMRgFUS) treatments, the acoustic and spatial heterogeneity of the skull cause reflection, absorption, and scattering of the acoustic beams. These effects depend on skull-specific parameters and can lead to patient-specific thermal responses to the same transducer power. In this work, the authors develop a simulation tool to help predict these different experimental responses using 3D heterogeneous tissue models based on the subject CT images...
September 2016: Medical Physics
Meaghan A O'Reilly, Ryan M Jones, Gabriel Birman, Kullervo Hynynen
PURPOSE: Transcranial focused ultrasound (FUS) shows great promise for a range of therapeutic applications in the brain. Current clinical investigations rely on the use of magnetic resonance imaging (MRI) to monitor treatments and for the registration of preoperative computed tomography (CT)-data to the MR images at the time of treatment to correct the sound aberrations caused by the skull. For some applications, MRI is not an appropriate choice for therapy monitoring and its cost may limit the accessibility of these treatments...
September 2016: Medical Physics
Karl D Price, Vivian W Sin, Charles Mougenot, Samuel Pichardo, Thomas Looi, Adam C Waspe, James M Drake
PURPOSE: Current treatment of intraventricular hemorrhage (IVH) involves cerebral shunt placement or an invasive brain surgery. Magnetic resonance-guided focused ultrasound (MRgFUS) applied to the brains of pediatric patients presents an opportunity to treat IVH in a noninvasive manner, termed "incision-less surgery." Current clinical and research focused ultrasound systems lack the capability to perform neonatal transcranial surgeries due to either range of motion or dexterity requirements...
September 2016: Medical Physics
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